1. Field of the Invention
The present invention relates to a process for sealing building joints commonly covered with flashing materials in building construction and the resulting building structure.
2. Description of Related Art
Water and air penetration into building structures is problematic. Water intrusion is a significant source of warranty repair costs to most production builders. Areas of water intrusion can also be areas of air intrusion, which diminishes the insulation value of a structure. One avenue for water an air intrusion is through flashing joints in open frame structures. A flashing joint is an interface between two structural elements that is protected from outside elements by flashing material. Building codes and practices require protecting flashing joints from air and water penetration from above the flashing material but can neglect air and water penetration from below the flashing.
One particularly troublesome flashing joint is that between a wall and a slab foundation with stucco cladding installation. Such a flashing joint uses a weep screed to cover the interface between a slab foundation and a sill plate of a wall above the slab foundation. Building codes require barrier material to shingle lap over the top of a weep screed to seal the top of the weep screed and to direct water from above the flashing joint away from the interface between the weep screed and wall. However, the bottom of a weep screed is typically unprotected. Strong winds can drive air and water up from the bottom of the weep screed, between the weep screed and slab foundation, into a wall cavity. Current building codes and building techniques lack specified protection from penetration into a wall cavity from the bottom interface of a weep screed and slap foundation.
Another troublesome flashing joint is that at roof-wall transitions when flashing remains uncovered on the roof deck, such as is found in clay tile roofing applications. As with the weep screed construction, barrier material is often applied over a portion of the flashing extending up the wall portion of the transition to protect from wind and water penetration from above. However, driving wind and rain can still penetrate between the roof and flashing and up between the flashing and wall into the wall cavity.
It is desirable to develop an easy and simple method to seal flashing joints in building structures from penetration of wind and water from beneath a flashing material into wall cavities.
U.S. Pat. No. 5,091,235 discloses a sill wrap assembly that provides some protection for foundation flashing joints. The sill wrap assembly includes a batt of infiltration barrier material that requires placement in the structural foundation during construction. The batt of infiltration barrier material is adhered to a sheet (a “sealing flap”) extending out from the foundation that can be sealed over the interface of the sill plate and slab foundation after the rest of the structure is assembled. The sealing flap has a strip of adhesive that can attach the sealing flap to the studs or outer sheathing of a structure. The sill wrap assembly must be installed during construction of the foundation of the structure leaving the sealing flap at risk of being damaged during construction of the remainder of the structure before being sealed over the sill plate-foundation interface. Additionally, the sill wrap has an adhesive strip that faces the studs of an open frame structure, which means adhesive will be exposed between studs allowing it to interfere with installing insulating to the stud spacing. Furthermore, the sill wrap design does not protect the wall cavity from wind and water that is driven up higher than the top of the sealing flap. The sill wrap is also not applicable to flashing joints other than those proximate to a foundation, and so is not applicable to roof-wall transitions.
It is desirable to develop an easy and simple method for protecting flashing joints in building structures from penetration of wind and water from beneath a flashing material into wall cavities. Moreover, it is desirable to identify a method for sealing flashing joints in a manner that can be introduced to a structure after constructing a structural frame and without exposing inter-stud spaces to adhesive strips. It is more desirable for such a method to be useful in applications using weep screed to provide better sealing of the corresponding flashing joint behind the weep screed than is achievable by current practices. It is further desirable for the method to be applicable to sealing many kinds of flashing joints as opposed to only those proximate to a structure's foundation. It is yet further desirable to provide a method for sealing flashing joints that will integrate with house wraps by providing a sealed joint between housewrap and the flashed joint seal thereby precluding water and wind from reaching a wall cavity from beneath flashing materials.